早熟和正常中华绒螯蟹大颚器官发育及超微结构

Development and ultrastructure of mandibular organ in precocious and normal Chinese mitten crab Eriocheir sinensis

对早熟和正常发育的中华绒螯蟹(Eriocheirsinensis)大颚器官(mandibularorgan,MO)进行解剖学和组织学研究,发现早熟蟹的MO在当年秋季已充分发育,MO细胞直径在当年11月达到最大值;而正常发育幼蟹的MO在当年细胞排列紧密,直到翌年秋季才充分发育。正常发育成蟹(二秋龄蟹)的MO细胞直径在10月达到最大值,明显大于早熟蟹(P<0.05)。表明早熟蟹MO较正常发育蟹提早一年发育,但是,秋季早熟蟹MO的发育速度和发育良好程度均不及二秋龄蟹MO的发育,这可能是早熟蟹卵黄发生过程较缓慢,较二秋龄蟹滞后约一个月达到次级卵黄发生末期的原因。中华绒螯蟹MO细胞超微结构的显著特征是丰富而形态多样的光面内质网和具小管状内嵴的线粒体,以及丰富的游离核糖体。

Anatomic and histological observations have been made for mandibular organ (MO) in precocious and normal Chinese mitten crabs (Eriocheir sinensis), and it was found that the MO of precocious crab well developed in autumn (1st year). The diameter of MO cell reached its maximum value in November. While the MO cells of juvenile normal crab were quite small and close arrangement in autumn (1st year), the MO was not developed until in autumn second year. The diameter of MO cell of adult normal crab (two autumn crab) reached its maximum value in October, and was much bigger than that of precocious crab (p<0.05). Therefore, the MO of precocious crab developed one year earlier than that of normal crab. In autumn, the speed and degree of MO development of precocions crab were more less than those of two autumn crab. This may be the reason for precocious crab to have slower vitellogenesis and one month delay reaching the late second vitellogenesis stage. The most distinguished features for ultrastructure of MO cells are rich in varied shapes of smooth endoplasmic reticulun, polymorphic mitochondria with tubular critae and numerous free ribosomes.